Roll bonding

Recent work has shown that tin may be deposited by an autocatalytic process using transition-metal ion reducing agents. Very thick coatings may also be economically applied to a variety of substrates by the process of roll bonding . 

V. Hydrocracker charge exchanger liquid with a small amount of hydrogen C-0.5Mo with Type 410S rolled bond clad. Extensive blistering and Assuring under clad. 

JJ. Base metal attack in a TP405 roll bond clad vessel. 

Transition joints are used to join dissimilar metals where flanged, screwed, or threaded connections are not practical. They are used when fusion welding of two dissimilar metals forms interfaces that are deficient in mechanical strength and the ability to keep the system leak-tight. Transition joints consist of a bimetallic composite, a stainless steel, and a particular kind of aluminum bonded together by some proprietary process. Some of the types in use throughout the cryogenic industry are friction- or inertia-welded bond, roll-bonded joint, explosion-bonded joint, and braze-bonded joint. 

The nickel-based systems include the flowing systems nickel—iron (Ni/Fe), nickel—cadmium (NiCd), nickel—metal hydrides (NiMH), nickel—hydrogen (Ni/ H2), and nickel—zinc (Ni/Zn). All nickel systems are based on the use of a nickel oxide active material (undergoing one valence change from charge to discharge or vice versa). The electrodes can be pocket type, sintered type, fibrous type, foam type, pasted type, or plastic roll-bonded type. All systems use an alkaline electrolyte, KOH. 

Corrosion-resistant metals and alloys, including stainless steels, nickel alloys, titanium, zirconium, and tantalum can be applied as linings or claddings to cheaper steel substrates. Most (>90%) are applied by roll bonding, but weld overlaying and explosive bonding are also used, as appropriate. Particularly expensive metals, such as tantalum, can be used as very thin ( 0.5 mm) loose linings. 

It contained 34 disks, 12 inches in diameter of Vg-inch-thick Transite. The hollow flat condenser plates, 35 in number, were roll-bonded from sheet copper. The unit was housed in a pressure vessel designed to allow the effect of total pressure level of air and other inert gases to be evaluated. 

Integral Bonded Cladding A composite material produced by roll bonding or explosion welding (EXW). 

The most common method is roll bonding which produces full sized sheets of clad (coated) material. The bond formed is partly mechanical and partly metallurgical consequently, metallurgically incompatible materials cannot be produced. 

Heat transport system piping in most PWRs (Fig. 1) is fabricated from carbon and low-alloy steels, for strength and economy, and clad with roll bonded or weld deposited corrosion-resistant cladding (either stainless steel or high-nickel alloys). Nickel-base alloys are used extensively as weld fillers for cladding and for joints between alloy steels and stainless steels for their superior corrosion resistance. 

NACE International RP-0199 Installation of Stainless Chromium-Nickel Steel and Nickel-Alloy Roll-Bonded and Explosion-Bonded Clad Plate in Air Pollution Control Equipment, NACE International, Houston, TX. 

Barrier coatings are of two types. The first consists of a thin surface layer of a more resistant metal. This can be accomplished by roll bonding (e.g.. stainless steel to non-heat-treatable aluminum alloys), by chrome plating, or by vapor deposit or ion deposition of a variety of metals. The latter methods are expensive and have size limitations. Unlike Alclad coatings, metal barrier coatings do not provide any electrochemical protection at a break in the coating. 

In roll bonding, layers of two metals are mated by heavy rolling in a mill after the surfaces have been thoroughly cleaned and treated. Clad thicknesses of 5 to 10 percent of the base steel thickness are common. Some small areas of unbonded metal will be present. Two metals may also be coextruded through a die. 

FIGURE 31.1 Roll-bonding process. (Courtesy of Evercel Corp.)... 

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